REDLINE

Hello forum people. Well, it seems that my main cat is clogged. I have to replace it, but was wondering what my options were. I'm trying to keep it stock for reliability and cost issues, but aftermarket just seems more affordable than OEM. My quesion is, if I want to get a main cat, which one should I get? I know a new OEM main cat (my first choice) costs around $1200.....way too much....I also heard about Bonez Hi-flow from rx7.com, and also heard about Random (although I heard they have some problems). My concern is running lean....currently my only mod is an HKS Downpipe. If I add a hi-flow, will I need an ECU upgrade? I know the rule of thumb is 3 mods and upgrade, but I'm just asking the people with experience to be sure. Thanks again People!!

Mahjik

iTrader: (1)

You should be fine not getting an ECU and adding a hi-flo cat. If you look to add an aftermarket intake, then you should look into upgrading the ECU.

As far as the different hi-flos, I've never heard a bad thing about any of them. I have heard that the Bonez hi-flos last longer than the others, but don't flow quite as well. Never saw any tests done or anything to prove that, or to prove that any of them are worse or better than any other one.

dclin

iTrader: (4)

I've no problems with my Random Tech, though only had it for about 7K miles. Peeked inside about 1K miles ago, and it looked fine. Keep in mind that alot times when someone has a bad experience, its is sometimes due to something they did not understand or did wrong.

In the case of putting a hi-flow cat in, make sure you hook up the air-pump to it like before. Not saying that whoever had their problems with a Random hi-flow cat did not do so, but many times people are quick to blame a product rather then the implementation/mis-use/etc.

Keep in mind for the Random hi-flow, you will have to cut the flange of the airpipe end that connects to the stock cat, and put a piece of tubing (with worm clamps to secure each end) to connect the airpipe to the Random cat.

Also,the Random also comes with one end pipe not welded on. When you install, you would slip the loose end pipe over one end of the cat, adjust the position, then weld. I suppose this is to allow for any slight differnces between the positioning of different cat back piping.

All this is not really a big deal if you have access to the proper equipment. If not, any muffler shop worth going to can easily do this for you for a reasonable amount.

Hope that helps!

justin

I got a bonez and never looked back.
Went to track with ran 12.3 then put midpipe on and ran the same et but 1 mph faster...
Almost no difference.I was surprised to say the least

Decay

Kinda confused by this...first you say you never looked back after getting one, then you say you saw no difference...well which is it?

SleepR1

No problems since 1998 and 55,000 miles with stock ECU. I have an RB intake duct, K&N-in-stock airbox, Trust catback. The boost had to be dialed down with a "10.5" psi boost control pill that replaces the stock pill in the waste gate. Without boost tuning, I was getting 15 psi spikes (not good with stock ECU). Talk to Trey Cobb or Arie Yallon. They'll supply you with the right pill (the pills are sold separately BTW). You may need to try more than one...(I had to).

The Bonez is completely bolt-up with no welding needed. You will need to dispense with the cheezy rubber hose and screw clamp RP sends you to hook up to the air pipe (the flange must be cut as declin points out).

Instead use a 5/8-inch brass compression coupler fitting. With the right amount of torque, the fitting is airtight, and works very reliably without the stupid rubber hose melting and falling off (been there, done that 3 hoses ago!). I don't know why RP just doesn't supply you with the 5/8-inch brass compression coupler fitting. It's $2.75 at your local hardware store!!

Good luck!

3rdGenLuvr

Is there anyway of testing/seeing if a cat is clogged or close to it?

Reason why I ask is my 96 Ram truck died on me the other day. I cldnt figure it out, it wld top out at like 25mph then start boggin. If I had to guess I wld say anythng over 3500rpm(no tach) wld break up and bog. I had similiar experiences w/ other cars.....one time it was the O2 sensor, the other a bad fuel pump. Someone told me a clogged fuel filter cld cause the same symptoms. ANYWAY, it was a clogged cat! EOS. (thought some of you wld like to put these symptoms in ur memory bank just in case)

Gdluck w/ ur purchase!

Sled Driver

iTrader: (9)

Remove the O2 sensor. It will make alot of noise, but if your main cat is clogged the back pressure will relieved.

Drive the car & see if you feel the diferance under boost.
Usually a clogged cat will limit rpms & boost pressure, to some extent.

Since you don't want to run boost with a cold motor, you'll need to remove the sensor with the engine up to temp, 1st.

Now don't drive around for days with the O2 sensor out & burn a hole in your body. Keep it a short test drive.

You will get a "Check Engine" light because the O2 sensor will show a fault.
After the test, reinstall the O2 sensor, pull the neg cable from the battery, step on the brake pedal, reconnect the battery cable.
That will reset your ECU & Eng Ck light

REDLINE

Thanks for the info guys. Couple questions....whats RP? and what do you think my boost pattern will be if I have an HKS downpipe, Bonez hi-flow and stock everything else? I'm seriously considering the Bonez now....only problem is that my turbos are from a '95, so restrictor pills are no longer used....will I have to drill out the nipples? Thanks people.

rynberg

RP stands for Rotary Performance out of Garland, TX. You have been on their website, rx7.com.

justin

After I installed my bonez high flow I ran a 12.3.
I went back to track the next week with the midpipe installed thinking that now I might have a chance
at a 12.0 or close to that now that there was no restriction.
I ran the same et w/the same 60'time.
I did'nt go any faster with the high flow cat off so now I just leave it on

SleepR1

Yeah, but I bet you shot cool flames with the midpipe in place The Hi-flow cat doesn't allow flammage

Want2race

I have the ATR hiflo cat.... i like it... Flows well and should pass emmisions... Welds where magnificient!

Im not prepared to pay the big $10k fine.... thats just ghey!

3rdGenLuvr

Was the ATR cat a direct fit or does it need to be welded?

REDLINE

Well? Can anyone predict my future boost patterns? Right now with HKS downpipe, I still get 10-7-10 pattern...only problem is, due to clogged cat., right after 2nd turbo kicks in, it right away drops down to 5 psi and fluctuates (jumps around) 5-7 psi until redline.....

KINETIK_FD3S

so you cant shoot out flames with a high flow cat?

SleepR1

I'm afraid not